The SoC on the BBB is definitely capable of 8 channel output, at what sample rate I am not sure yet. But if I read the McASP datasheet it sounds like probably 192Khz. This would likely come down to memory bandwidth. If I get confident enough to write a driver, or someone better than myself does it... I will give it a go.
Let me see if I understand the essence of this innovation
We have long used embedded devices running Linux/MPD connected to router with music on a NAS. I run such a beast based on ALIX pumping bits out on USB to WaveIO (or other USB to I2S converter) then to I2S on a DAC.
Am I correct that what you are doing here is eliminating the USB and the WaveIO? The RPi converts directly to I2S?
I can see how this can be significant for many reasons. Every conversion is a mess and even Async USB appears to get in the way more than one would expect.
Timing is perfect as I am just tooling up my next music server and not too late to switch to RPi or BBB.
Walter
We have long used embedded devices running Linux/MPD connected to router with music on a NAS. I run such a beast based on ALIX pumping bits out on USB to WaveIO (or other USB to I2S converter) then to I2S on a DAC.
Am I correct that what you are doing here is eliminating the USB and the WaveIO? The RPi converts directly to I2S?
I can see how this can be significant for many reasons. Every conversion is a mess and even Async USB appears to get in the way more than one would expect.
Timing is perfect as I am just tooling up my next music server and not too late to switch to RPi or BBB.
Walter
Yes. All you need is a router with an SMB/CIFS server ie. a network fileserver function. In your TL-WR1043ND's menu, this is called "Storage Sharing". You can ignore the "Media Server" section in the menu - that's an added layer of software kludge which is not needed if you are running MPD as your music server (on your embedded computer).
No. An AirPlay receiver sits there passively, receiving and "rendering" audio (and/or video) streams. The audio stream is sent to the AirPlay receiver by an Apple product: a personal computer running iTunes (Mac or Windows), or an iPod/iPhone/iPad. FLAC users beware - you will need third-party software before any of these Apple products will play FLAC files!!
Also, the way that MacOS processes audio is, arguably, less than ideal for high fidelity audio playback, so with a Mac computer you might wish to consider third-party audio engine replacements; Pure Music, Amarra, Audirvana etc.
All things considered, you would probably choose the AirPlay receiver option only if you had already invested in Apple's "ecosystem" of products.
Just to be clear - the AirPlay receiver scenario involves true streaming, but the MPD option, which is the main option under discussion here, is not true streaming - it involves direct file access across a network. At this stage, this appears the better option.
The SoC on the BBB is definitely capable of 8 channel output, at what sample rate I am not sure yet. But if I read the McASP datasheet it sounds like probably 192Khz. This would likely come down to memory bandwidth. If I get confident enough to write a driver, or someone better than myself does it... I will give it a go.
Russ,
I think the potential of this is to have a source of multichannell I2S and video HDMI at the same time. That would be great !!!
This would "fix" the lack on the market of a HDMI->I2S converter for home theater DIY.
D.
> the lack on the market of a HDMI->I2S converter for home theater DIY.
HDMI Stripper has been available from the internets for a long time...
It will not decode DTS, Dolby, etc, etc, though. For that you need to buy licenses, which generally come in the form of an AV receiver.
Or you could use a PC player which does the decoding and outputs multichannel audio over HDMI. But in that case, why even bother with audio over HDMI, since the PC will also have a USB port ... or direct I2S output if the PC is a Pi...
> I think the potential of this is to have a source
> of multichannell I2S and video HDMI at the same time.
But, these boards only output 12 bit color, not 24 bit, thus image quality could be low for movie playback. Some people also report it is not powerful enough to decode all forms of HD video, skipping and stuttering, etc, while others say it works perfect.
HDMI Stripper has been available from the internets for a long time...
It will not decode DTS, Dolby, etc, etc, though. For that you need to buy licenses, which generally come in the form of an AV receiver.
Or you could use a PC player which does the decoding and outputs multichannel audio over HDMI. But in that case, why even bother with audio over HDMI, since the PC will also have a USB port ... or direct I2S output if the PC is a Pi...
> I think the potential of this is to have a source
> of multichannell I2S and video HDMI at the same time.
But, these boards only output 12 bit color, not 24 bit, thus image quality could be low for movie playback. Some people also report it is not powerful enough to decode all forms of HD video, skipping and stuttering, etc, while others say it works perfect.
Ok to try to recap, since I've bought a BBB and it will probably lay there for a while by the time i can get all info:
1) The guide on computer Audiophile shows how to Build a BBB MPD using USB out, Not I2S ?
2) Mikelangeloz is preparing new Volumio BBB distro.
3) The main clock on BBB only offers 48 and 96Khz ( http://www.runeaudio.com/forum/mpd-is-not-offering-any-audio-output-t100-30.html)?
4) Maybe TP is working on a cape, maybe not, it's not clear to me yet
If a clever guy would put a project of a MPD using good I2s and no headaches for the user on kickstarter he would surely sell like hotcakes.
Enough said.
1) The guide on computer Audiophile shows how to Build a BBB MPD using USB out, Not I2S ?
2) Mikelangeloz is preparing new Volumio BBB distro.
3) The main clock on BBB only offers 48 and 96Khz ( http://www.runeaudio.com/forum/mpd-is-not-offering-any-audio-output-t100-30.html)?
4) Maybe TP is working on a cape, maybe not, it's not clear to me yet
If a clever guy would put a project of a MPD using good I2s and no headaches for the user on kickstarter he would surely sell like hotcakes.
Enough said.
I think what this thread is exploring... that with a rasberry pi or beagle bone you can bypass usb and get i2s straight out with a lot less jitter and closer to the holly grail of bit perfect with all the bits in the right time sequence.
I posted that question earlier but no one in the know chose to grace me with a confirmation.
Perhaps it has gone underground as someone has realized there is a product opportunity and time to clam up. Who knows. Sounds promising. I'll stick with current usb approach and let this mature a bit. It will develop in open source so a community will spring up and we will all benefit in time.
DSD source; cheap available open source hdw. Perhaps a triode filter to replace the DAC.
Keep your turntable as your grand kids will one day say really? Grooves in vinyl? Wow, was it powered by a steam engine?
I posted that question earlier but no one in the know chose to grace me with a confirmation.
Perhaps it has gone underground as someone has realized there is a product opportunity and time to clam up. Who knows. Sounds promising. I'll stick with current usb approach and let this mature a bit. It will develop in open source so a community will spring up and we will all benefit in time.
DSD source; cheap available open source hdw. Perhaps a triode filter to replace the DAC.
Keep your turntable as your grand kids will one day say really? Grooves in vinyl? Wow, was it powered by a steam engine?
Hey guys, don't let my silence phase you. I have just been busy.
I am still exploring the ALSA code in regard BBB. I can confirm that there is no reason at least 192khz is not possible - and very likely 384khz.
I just have not had a lot of free time to play with it.
I do plan on producing a very DIY friendly cape for BBB if it pans out.
Otherwise I can do one for rpi. Who knows maybe both.
I am just still doing a lot of discovery in terms of the software and hardware.
I have just been busy.I am still exploring the ALSA code in regard BBB. I can confirm that there is no reason at least 192khz is not possible - and very likely 384khz.
I just have not had a lot of free time to play with it.
I do plan on producing a very DIY friendly cape for BBB if it pans out.
Otherwise I can do one for rpi. Who knows maybe both.
I am just still doing a lot of discovery in terms of the software and hardware.
Russ, if I understand correctly others have observed 44.1khz being upsampled to 48khz by the current drivers as a result of a restriction of the BBB board clocks, thus unable to produce bit-perfect I2S signal from a typical CD based input file.
Do your investigations show a possible solution to that?
Do your investigations show a possible solution to that?
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@ wlowes my question is different from yours, as to your question someone by the tag "LowOrbit" has done the I2s with the Buffalo III DAC over at
tirnahifi.org on the computer audio forum under Tweakers Rash.
Hi Mark
That's me, over on Tirna.
TBH I am a complete numpty with Linux but I got the I2S working with the RPi in less than an hour. The problem for us all is that there isn't a single place with ALL the info in a handy package.
If you review Russ' first post in this thread almost everything you need to get going is there. Pinout, sound config and pointers to the easiest software approach which is probably, but not exclusively, Volumio at this point.
I was very surprised when it all worked. My history with Linux audio has been frustrating, with wifi issues and NAS issues being high on the list and the seemingly obtuse way Linux handles sound files. Getting bit perfect audio out is no easier than with a pc, but it is doable and there are switched on people across the globe working to make this happen and easily for us.
Mark
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I can't think of more ways so say yes. It is just a matter of making it practical.
It all about which ALSA drivers are loaded/used - and how mpd is set up.
Hello people, i'm developing an acoustic analyzer unit based on the BBB with the "Audio Cape", my intention is to replace this cape for a better audio quality. I'm struggling very hard to make ASoC to recognize my custom ADC as a soundcard (i'm currently working with the ti pcm1803a which doesn't have I2C control interface).
Looking forward for reading your progress with the BBB!
Regards
Looking forward for reading your progress with the BBB!
Regards
I can't think of more ways so say yes. It is just a matter of making it practical.
It all about which ALSA drivers are loaded/used - and how mpd is set up.
Thanks Russ. I assume that once the drivers are developed the solution will aply to more than just MPD? I use Squeezelite, to date, with USM DACs, as long as the drivers are loaded SL seems happy.
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